In the art of electrophotography, there is a need for relatively low fusing temperature toner powders. These toners not only reduce power consumption and copier warm up time, but also increase the duty life of machine components in copiers because of inherent reduced heat spillage from the fuser subsystem. These toners also permit higher speed fusing and reduce problems with paper receivers.
To achieve such results, various approaches have been tried. One approach has been to use low molecular weight linear amorphous polymers, with a low T.sub.g. However, these polymers result in poor toner powder keeping characteristics and very little offset latitude. They also require the use of excessive wicking fluid quantities.
Another approach has been to use cross-linked polyester toners that utilize low molecular weight polymers that are cross-linked to provide suitable offset latitudes. However, these toners suffer from fusing temperatures that are too high.
Still another approach has been to use blends of crystalline and amorphous resins to reduce toner fusing temperatures (as taught in Japanese Laid-Open patent application Kokai No. 65146/1981). However, toners of these blends display poor keeping properties.
So far as now known, prior art approaches have not solved the problem of producing a low fusing temperature toner powder with desired keeping and grindability characteristics.